The biddies revisit California as part of the volcanic wine passport tour. Several AVAs within both Napa and Sonoma counties have volcanic soil and volcanic wine. Tune in to learn where to find it and what it’s all about.



  • Volcanic Wines: Salt, Grit and Power by John Szabo

Study Notes:

*Please note some of these lines might be directly taken from sources noted above.

  • Falls along the Pacific Rim of Fire like the PNW
  • A bunch of plates slammed into each other and made volcanoes a thing here
  • San Andreas Fault – a very unstable fault that Kara (HI KARA) is very afraid of
    • Caused by three tectonic plates converging together
    • This junction reached northern california seven million years ago and created a very apocalyptic era as noted by the remnants of diverse volcanic ashes, tufts, pyroclastic material, lahars and abundant
    • In SF earthquake of 1906 the fault slipped 16 feet nearly destroying the city
  • Sonoma Volcanics – the official name of the geological formation that forms the majority of of the eastern half of Sonoma wine country and many parts of Napa
  • Not the volcano structure that you think of but more crinkles in the earth or fissures that would erupt
  • Both the Vaca Range and the Mayacama range feature volcanic landscapes
    • Mayacamas range is what separates Napa and Sonoma
  • Clear Lake Volcanic Field – a volcanic caldera lake with some of the youngest volcanic soils in CA
    • Still sits on a massive volcanic complex with a powerful underlying magma chamber that powers the world’s largest geothermal power plant
    • Mt. Konocti on this field is officially listed as dormant but is still listed as a “high” threat potetnail
    • Vineyars in this areare limited with remnants of black volcanic glass callled obsidian ranging in size from small stones to small cars and is leftover from when Mt Konocti erupted 11,000 years ago

NAPA – Mountain vs. Valley Wine

  • Genuine mountain wines are from stony, low fertility, free draining hillsides so are denser, darker, and more tannic
  • Virtually all of the volcanic wines in Napa are mountain wines
  • There are 16 sub AVAs within the Napa Valley AVA but about half of them are volcanic


  • Coombsville AVA
    • Cool climate, best known for its Cab
    • Also grows Chardonnay, Carmenere, Syrah and Pinot Noir
    • Voclanic ash from nearby Mount George in the soil holds water welland keeps the grapes hydrated
  • Stags Leap District
    • Alluvial and colluvial soils underpinned by clay and volcanic soils – creates a loose HI CALLA free-draining soil that focus cabernet vines to grow strong, deep roots, leading to healthier vines and high quality grapes
    • The Stags Leap name comes from the legend that a great stag, being pursued by hunters, made a seemingly impossible leap between the two rocky peaks that sit high above the valley. This name has been a source of some controversy – specifically the absent possessive apostrophe.
    • Two producers founded in the 1970s – Stags’ Leap Winery (now as well known for its Petite Sirah as for its Cabernet Sauvignon) and Stag’s Leap Wine Cellars (founded by Warren Winiarski) – came to legal blows in the mid-1980s over the name. The former was accused of benefitting from the publicity gained by the latter in the infamous Judgement of Paris tasting.
    • The subsequent ruling was that each would keep the Stags Leap name, but with a distinct apostrophe placement. In the late 1980s, the two producers banded together to fight for the creation of the official Stags Leap District in 1989. That AVA would eschew the apostrophe altogether.
    • Other wineries: Shafer Vineyards, Chimney Rock and Clos du Val
    • Mostly Cab and Bordeaux Blend Red
  • Howell Mountain
    • Located in Vaca mountain range, there is no actual Howell Mountain (named for a township)
    • To be part of the AVA, grapes must be grown above 1400 feet
    • Warm days and cool nights give grapes a “celebrated acid structure and aromatic depth”
    • Cabernet, Merlot, Zinfandel, Petite Syrah, Viognier, Chardonnay


  • Napa = bougie, Sonoma = sleepier
  • Has a much longer history than Napa
  • Russians planted grapes out at Fort Ross on the Coast a quarter century before George Yount planted grapes in the Napa Valley
  • Birthplace or modern California wine due to the Hungarian Count Agoston Haraszthy
    • Fun facts – he was also a founder of a small town in Wisconsin, sheriff of San Diego and creator of Sonomas Buena Vista Winery and the ultimate suitcase clone supplier
    • He was sponsored by the CA governor to go to return to Europe and collected nearly 500 grape variety cuttings
    • Lost all his money and grapes to phylloxera in the late 1800s and apparently died in Nicaragua in a crocodile attack
  • 16 sub AVAs in Sonoma – 11 volcanic
  • Greatest collection of these lie inland east of the solidified Wilson-Grove Sea
    • An “impressive series of gaping fissure was violently voiding the bowels of the earth” in an area now roughly defined byMt St Helena south to Carneros and Sonoma Mountain east to the Vaca mountain range
  • Moon Mountain is Sonoma’s most volcanic


  • Alexander Valley
    • Runs alongside Russian River
    • Notable wineries: Clos du Bois, Francis Ford Coppola Winery
    •  Alexander Valley is 22 miles long, has 26 wineries and 130 grape growers. It is known for its world-famous Cabernet Sauvignon, and other Bordeaux varieties such as Merlot, Malbec and Sauvignon Blanc.
  • Chalk Hill
    • Chalk Hill is a sub-appellation of the Rusian River Valley in north of Sonoma, California. Its unique terroir in the hills means that it is slightly warmer than many of the surrounding AVAs, and is planted to Bordeaux varieties like Cabernet Sauvignon and Merlot, as well as Chardonnay and Sauvignon Blanc.
    • Can be warmer than the rest of the Russian River Valley wines since it sits on the hills above fog
  • Dry Creek
    • Location in Northern Sonoma County on the West side of 101, the Dry Creek Valley Wine Association was created in 1989. It is made up of 60+ wineries and 150 grape growers. They share a commitment to growing high-quality fruit to produce world-class wines and an interest in sustainable farming practices to ensure a pristine valley for future generations.   Dry Creek Valley is world-famous for its big, hearty Zinfandels, as well as Sauvignon Blanc and Rhone varietals.


Scents of toffee, roasted nuts, tobacco and vanilla. Flavors of clove, pepper, caramel, crème and cocoa. Dark and luscious, the 2019 Diamond Collection Claret brings together fragrant notes, good length, firm tannins, and sophisticated character, enhanced by a full body and long finish. 

Pairs well with a blue cheese burger, grilled lamb chops, and roasted herb turkey.

Blend: 78% Cabernet Sauvignon, 9% Petite Sirah, 6% Syrah, 5% Petit Verdot, 2% Segalin


The hills have some of the world’s largest and purest deposits of diatomaceous earth —a chalky substance consisting of fossilized hard-shelled algae, layered into the hillsides by earthquakes and volcanoes. (santa anita hills, russian river valley)